Public lists are of USERS and so if you have users that post mostly that subject then it would fulfill a similar role.

You can see it at work with the photography badge. https://beta.steempeak.com/b/badge-777777

There is perhaps ways to FILTER the feeds coming from badges. For example maybe a button or a page inside the badge that filters down the results to just a list of approved keywords or just one ... Exmaple set) #photography #photofeed #landscapephotography #weddingphotography

p.s. If you know someone who would like to curate a list like that let us know we're looking for testers and the badge will be free of cost for them.